Double-shell tube



(Model) v v W. T. MERSEREAU.

DOUBLE SHELL TUBE.

515558551. 5 Patented Apr. 21, 1896.

Fig- 17 6 ANDREW arm/mm. PuoTo-umuwAsniimmnvc ihvrrn \VTLLIAM T. MERSEREAU, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR OF ONE-HALF TO WILLIAM DURST, OF BROOKLYN, NElV YORK.

'DOUBLE-SHELL TUBE.

SPECIFICATION forming part of Letters Patent N 0. 558,651, dated April 21 1896. A hemi fil il January 11, 1896. $erial No. 575,145. (ModeL) To all whom it may concern.- the opposite side where the trough is con- Be it known that I, WILLIAM T. MERsE nected to the shell. The lips e and e are in- REAU,a citizen of the United States,residing clined at an acute angle to the shell D, so at South Orange, Essex county, New Jersey, that when pressed upon one another they will 5 5 5 have invented certain new and useful Iminterlockand formaseam of four thicknesses provements in Double-Shell Tubes, fully deto fill one side of the concave groove 0, and scribed and represented in the following the body of the reverse bend f is inclined respecification and the accompanyingdrawings, versely to the lip e, so thatwhen the seam is forming a part of the same. closed and the reverse bend is crushed it may 60' The object of this invention is to furnish draw the lips closely together. The shell an improved joint for the casings of double thus prepared is placed upon the inner tube, tubes, the joint being so constructed as to as shown in Fig. 2, and the whole is drawn draw the lips of the seam into especially close through a suitably-tapered hole in a die G, contact when they are closed upon the inner as shown in Fig. 4, the die being constructed 65 tube. Heretofore it has been common to with a circular aperture to gradually close make single or double lock seams by engagthe seam and to force the same wholly upon ing suitable lips upon the edges of a cylinthe interior of the shell. The reverse bend drical blank; but the present construction f, formed at one side of the trough f, oper- 'furnishesanadditionalelenienttosuchjoints, ates, when drawn through the die, to draw 70 by which one of the lips is drawn laterally in the trough laterally in the direction of the the operation of closing the joint, and the arrow 9 in Fig. 3, which tightly closes the lips are thus drawn into close contact, and joint, and brings the parts of the seam into any stretching of the metal which occurs in close contact laterally, the draft of such rethe closing of the same is fully compensated. verse bend operating gradually as the seam 75 The invention will be understood by referis closed, and thus serving to take up any ence to the annexed drawings, in whichstretch in the folds which is produced by Figure 1 is a cross-section of the inner pipe. crushing the lips closely together. Fig. 2 is a cross-section of the inner pipe with The formation of the reverse bend at one the shell applied thereto in readiness to close side of the trough produces afold of the shell, 80 the seam. Fig. 3 shows an enlarged view of which is extended longitudinally within the the edges of the shell adjacent to the seam. casing, at one side of the exterior joint, and Fig. 4 represents the die with a cross-section thus balances in a great degree the thickenof the completed tube as it is drawn through ing of the casing by the lips c e at the oppothe same. Fig. 5 is a cross-section of the site side of the joint. The entire seam is 8 5 3 5 completed seam and a portion of the inner thus made more symmetrical, and is thereby tube enlarged to show the construction of the better adapted to fill a symmetrical groove joint; and Fig. 6 is a longitudinal section of like the groove 0, and the construction also the tube, taken on line 6 6 in Figs. 4: and 5. avoids the excessive crushing of the folded A represents the inner pipe, having a lonlips at one edge of the same, which would be 90 o gitudinal butt-joint B at one side and a conrequired if they lay over one edge of a concave longitudinal groove 0 upon the opposite cave groove instead of lying in the middle of side. The casing is formed with acylindrical such groove, as shown in Fig. 5 herein.

exterior, and the seam located in the groove 0. A mandrel or core 11 is preferably support- D designates the shell, and E the completed ed within the tube during the drawing opera- 5 seam shown in Fig. 4. tion, one side of the mandrel being formed m Fig. 3 shows the adjacent edges of the shell, with concave groove h, into which the material one edge being provided with an inwardlyof the pipe A and seamE are forcibly pressed,

turned longitudinal lip e, and the opposite thuscrowding the different folds and flanges edge being formed with an inwardly-project of the seam into the closest possible contact 10a ing trough f, having an outwardly projecting with one another. With such a grooved manlip 6 upon one side and a reverse bend f at drel it isinnnaterial whether ornot the groove C be formed upon the inner pipe A prior to the application of the shell D and the drawing of both together through the die, as the pressure of the die will commonly press the scam upon the pipe A with sufficient force to drive one side of the pipe into the mandrelgroove h. Where the inner pipe is made of very considerable thickness, the groove 0 is formed upon such pipe before the shell is applied thereto.

In practice the die would be formed with suitable guides for the lips c c and trough f, to suitably close the seam; but I have not shown or claimed such features as they are already well known in the art.

I am aware that it is old to secure a casing upon a rod or tube by a plain lock-joint, and 1 therefore disclaim such method of construction broadly.

In my construction the casing-blank is formed in cylindrical shape and provided with the lips to make a lock-joint, and is then applied to the tube and drawn through the dies, and any variation in the diameter of the casing or tube would, unless means for compensating for such variation were provided, sometimes result in fitting the casing loosely to the tube. I therefore provide one edge of the casing with an additional element or member adapted, when bent in closing the seam, to draw the lips positively toward one another, and to continue such draft during the act of lockin g and closing the seam until the seam is wholly finished. Such member is supplemental to the ordinary lips, and performs a novel function in tightening the seam as the joint is closed and in taking up the slack or expansion of the metal, which is liable to exist or to be produced by pressing the same.

My invention is especially designed for applying a steel casing to a butt-joint tube of the same material, and as such material is very rigid I find it preferable to use, in the process of closing the seam, a mandrel H, provided with the groove h, which fits and supports the groove C upon the side of the inner pipe, and secures the effective closing of the seam by holding the same in firm contact with the wall of the die. I have therefore claimed a casing-blank provided not only with the lips e and 6, but with a supplemental member to maintain the tightening of the joint during the closing of the seam, as well as the specific form of the completed article in which the fold 6 which is formed by the bend f, projects at one side of the exterior joint, while the folded lips project at the opposite side.

What I claim as my invention, and desire to secure by Letters Patent, is

1. A blank for a tube-casing, consisting of the cylindrical shell D having one edge provided with the inwardly-turned inclined lip e,

and the other edge provided with the outwardly-turned inclined lip to engage the same, and with a member adapted, when bent in closing the seam, to draw the lips positively toward one another and to continue such draft during the act of locking and closing the seam until the seam is wholly finished, substantially as herein set forth.

2. The double tube, consisting of the inner pipe A having butt-joint B upon one side and concave groove 0 upon the opposite side, and the casing formed of the shell D having the lock-joint seam with the engaging lips c, 6', upon one side of the joint, and the fold c projected within the opposite side of the joint, the shell being cylindrical upon the outer side and the lips and the fold e projecting upon the inner side of the shell, substantially as herein set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

WILLIAM 'l. MERSEREAU.

\Vitnesses:

WILLIAM F. DURST, THOMAS S. CRANE. 

